Internal combustion engine



June 29, 1943. w GLAMANN 2,323,028

INTERNAL COMBUSTION ENGINE Filed June 28', 1940 2 Sheets-Sheet 1 ATTORNEYS June 29, 1943. w. GLAMANN INTERNAL COMBUSTION ENGINE Filed June' 2a,1940 2 Sheets-Sheet 2 ATTORNEYJ ENGINES.

Patented June 29, 1943 INTERNAL COMBUSTION ENGINE Wilhelm Glamann,Stuttgart, Germany; vested in the Alien Property Custodian ApplicationJune 28, 1940, Serial No. 342,882 In Germany April 27, 1939 (Cl. 12S-32)2 Claims.

The invention relates to an internal combustion engine particularly ofthe fuel injection spark ignition type.

The object of the invention is to lessen the inclination of the engineto knock, specially under high loads at high temperatures. A furtherobject of the invention consists in means for producing a most uniformmixture of air and fuel in the engine cylinder, in order to create inthis way an increase of the output of the engine, and a most favorablefuel consumption.

A further object of the invention lies in the safety of operation of theengine, guaranteed by a favorable cooling of highly stressed parts bymeans of the fuel jet.

An important characteristic of the invention consists in the fact thatthe combustion space formed between the piston head and the endwall ofthe cylinder is divided into a main combustion chamber, formed by arecess in the piston head, preferably laterally transposed relative tothe cylinder axis, and a flatter combustion space, being located betweenthe remaining part of the piston head and the endwall of the cylinder orthe cylinder head. In the extreme case this flatter combustion spacecould approach the zero value, the piston head in this place approachingvery closely to the cylinder head.

The ignition device serving for igniting the mixture is preferablyplaced in the flatter combustion space, while the injecting nozzledischarges into the main combustion space. Furthermore the inlet valveor valves are preferably arranged above the main combustion space, andthe outlet valves within the fiatter part of the combustion space. Ofspecial advantage is the arrangement of the ignition device in theflatter part of the combustion space formed by the piston head and theend wall of the cylinder, particularly also for the reason that by thesemeans a shock-like pressure wave which might be the cause for knockingsymptoms will be avoided, but on the other hand the ignition wave wouldbe able to advance with greater speed in the combustion chamber, as inthe igniting moment, at the end of the compression stroke a currentexists, flowing from the flatter part of the combustion space into themain combustion chamber, and has the same direction as the spreadingignition wave, accelerating the latter.

Further advantages of the invention are evident from the followingdescription.

The invention is specially important for engines strongly loaded andoperating at high temperatures, like aeroplane motors and the like whichare mostly equipped with more than two valves supported in the cylindercover. It is generally applicable to mixture compressing engines withseparate ignition, but specially important for such engines in which alight fuel, which inclines particularly to knocking symptoms, isinjected directly into the cylinder space of the engine.

Further objects and advantages of this invention will be apparent fromconsideration of the specification as illustrated by the accompanyingdrawings of possible embodiments of the invention, in which drawings:

Fig. 1 shows a cylinder of an internal combustion engine in a view fromabove.

Fig. 2 shows a section through the cylinder and the piston in the lineA-A of Fig. l.

Fig. 3 shows a section through the cylinder along the line B-B of Fig. land a view of the piston, the piston being shown in elevation.

Fig. 4 is a plan view of a somewhat altered type.

Fig. 5 shows a section through the cylinder along the line C-C of Fig.4, the inlet valve being opened.

Fig. 6 shows a section through the line D--D of Fig. 4.

With the type shown in the Figs. 1 to 3, in the cylinder I0 a piston IIis sliding, the bottom of which is provided with a recess I3 arranged onone side, forming in the upper dead center of the piston the maincombustion chamber of the engine, while between the remaining notrecessed part of the piston bottom and the wall of the cylinder head ashallow partial combustion space I4 is formed.

The inlet valves l5 are arranged above the main combustion chamber I3,the outlet valves I8 above the not recessed piston bottom. The injectingnozzle I6 discharges into the main combustion chamber I3, while thespark plugs Il are located aside of the main combustion chamber I3 inthe zone of the cylinder wall lying next to the not recessed part of thepiston head I2. In the example shown they are arranged in the cylinderwall, in the place of greatest distance from the combustion chamber, insuch manner that when the piston Il finishes its inward stroke. they areplaced in lateral pockets I9 of the piston bottom, and are protected bythe piston head against the main combustion chamber.

The type shown in the Figs. 4 to 6 is distinguished from the oneaccording to Figs. 1 to 3 substantially by the fact that the ignitingplugs I'I instead of being arranged in recessed cavities I9 are placedin back of the conical slope I9 of the piston rim.

Adjacent the passage 20 towards the combustion chamber, the not recessedpart of the piston I2 is formed with an upwardly extending ridge 24, sothat at this place it lies somewhat higher than the point of ignitionI'I and forms a throttling place between the shallow part I4 of thecombustion space and the main combustion chamber I3. l

The passage 20 between the recess I3 and the not recessed part of thepiston bottom I2 is rounded with a comparatively large radius.Furthermore this passage is followed `at both sides by ridges 28, alsowith smoothly rounded passages formed by the piston body 22 whichremains here in its full height, and which passes again at 29 ultimatelyinto the lower part 23 of the piston body.

The outer wall of the recess I3 formed by the piston body 22 is in itspart 23 which is turned towards the injection nozzle I6, formed lesshigh than the remaining side wall of the recess, and is besides wellrounded at its upper edge 26, so that the fresh air being sucked induring the downward stroke of the piston through the inlet valves I4 inthe direction of the arrows 2'I (Fig. 5) may stream unrestrained intothe cylinder in order to mix with the vaporous fuel.

The modus operandi of the engine is as follows:

During the suction stroke of the piston, air is sucked through the inletvalves I5 which air will be compressed during the following compressionstroke in the upper part of the cylinder I0. Concomitantly with theentry of the air, the fuel, a light fuel like petrol or gasoline in finevaporisation is injected through the injection nozzle I6 across the maincombustion chamber and, past the inlet valves, directed to the oppositeside of the main combustion chamber. Herewith it mixes as well with theair entering through the inlet valves as also with the air streamingalternatively between the partial spaces I3 and I4, so that by athorough mixing a uniform combustion mixture will be formed.

When following to the suction stroke the piston I I again moves upwardin order to compress the fuel-air mixture contained in the cylinder. themixture in the last part of the compressing stroke will be compressed bythe not recessed part of the piston head I2 working in a way asdisplacer, mainly into the recess I3 of the piston head (Fig. 2),causing a lively motion of the mixture in the direction of the arrows 2Iand a very thorough uniformity of the mixture. If now the mixture isignited in one place shortly before the piston reaches its inner deadcenter, by means of the ignition plugs I'I, the not recessed displacerpart of the piston drives the ignition flame at the end of thecompression stroke with great velocity but under thorough control intothe recess I3 where the main portion of the mixture will be ignited, sothat the recess I3 acts as combustion chamber or better as maincombustion chamber. The passage of the combustion chamber I3 into thenot recessed part of the piston head being rounded on all sides, thestreaming of the partly already ignited mixture into the combustionchamber ensues without forming any disturbing marginal eddies on sharpedges of passages or the like, which might cause an uncontrolledignition of the mixture. On the contrary the propagation of the ignitionflame and with it the ignition of the mixture ensues in the engine builtin accordance with the invention in a compulsory manner, controlled bythe movement of the piston, the cooling metal walls of the not recessedpart of the piston head and of the cylinder head preventing theinvoluntary and fast spreading of the ignition flame in the narrowcrevice being formed between these parts, at the end of the stroke, bymeans of radiation or by pressures waves in the direction to thecombustion chamber.

The burning mixture drives the piston powerproducing downward, whereuponduring the following upward stroke of the piston, the combustion gaseswill be expelled through the outlet valves I8 from the cylinder I0.

As also in the upper dead center of the piston the injection nozzle I6will not be covered by the piston, the injection of new fuel can bestarted immediately after the termination of the exhaust stroke,producing thereby a good mixing of the fuel with the incoming fresh air.Herewith the fuel jets 30 meet mostly the rounded passage place 20between the main combustion chamber and the not recessed part of thepiston head, so that this place which is inclined to be easilyoverheated, will be very effectively cooled by the delivery of heatnecessary for the evaporation of the fuel. Part of the fuel will bedeviated at the passage place 20 towards the outlet valves I8 in orderto cool them also, while the remainder of the fuel comes during thefollowing downward stroke of the piston near to the spark plugs I1,producing here a particularly good mixture, very apt to be ignited, andpreventing simultaneously an overheating of the spark plugs.

It has been found that when using the above described arrangement it ispossible to make use of fuels with a substantially lower octane factorthan usual, also in internal combustion engines of the high performancetype, for instance in aeroplane motors without special inclination ofthe engine to knock, the compression not necessarily being decreased andno decrease of the output and no increase of the fuel consumption beingevident. On the other hand with fuels of usual octane factors thecompression may be increased without an inclination of the engine toknock being noticed, while at the same time a decrease of the specificfuei consumption is found.

The cause for this important; result is to be seen in the fact that bythe arrangement of the spark plugs according to the invention it hasbeen prevented that within the mixture, compressed almost to theself-ignition limit, blowlike acting pressure waves would have beenformed, issuing from the place of ignition, and preceding the ignitionfiame, and causing a detonation-like combustion of the mixture in thecombustion chamber.

By the fact that the ignition flame spreading from the igniting placeshas to pass through the comparatively low space between the coolingmetal walls of the cylinder head and the not recessed part of the pistonhead, the flame is kept comparatively cool. Therefore it cannot producein the parts of the mixture which it first meets so great an impact,that dangerous pressure waves will be created within the mixture. Here-With also the throttling place provided at 24 may be found of advantage.On the other hand the ignition flame has the opportunity on its way fromthe place of ignition to the combustion chamber to spread to both sides,so that v' ENGINES.

at the main combustion chamber a broad flame front arrives actuallycausing a pure flame ignition, and therewith an exact control of theignition time within the main combustion chamber.

Although the spark plugs are arranged on the side of the flatter part ofthe combustion space, opposite to the main combustion chamber i. e. asfar away as possible from the hottest part of the charge in thecombustion chamber, they are simultaneously protected againstoverheating, so that also a substantial cause for a premature red-hotignition of the mixture will be eliminated. The same may be said of theposition of the outlet valves I8, if these, as shown in the illustratedexample, are arranged above the not recessed part of the piston head.Such an arrangement is most favorable if two outlet valves are provided.

Having now particularly described and ascertained the nature of myinvention and several ways in which it may be applied, I declare thatwhat I claim is:

1. In an internal combustion engine an engine cylinder, a piston movabletherein, the pisuuu' vul ton head being shaped in such manner relativeto the cylinder head that at least two combustion spaces are formed onecomprising a shallow space and the other an enlarged space, the pistonhead being formed with a transversely extending ridge adjacent theshallow space acting to guide mixture flowing from the shallow space tothe enlarged space.

2. In an internal combustion engine an engine cylinder, a piston movablein it, a recess at one side of the piston head forming a mainrcombustion space, while the opposite part of the piston head extendscomparatively near to the end wall of the cylinder when the piston is atouter dead center, an injecting nozzle arranged in the lateral cylinderwall on the side of the recess, and a rim upon the piston head risingabove the bottom of said recess being however lower than the part of thepiston head opposite to the recess, so that the fuel jet injected by thenozzle can be issued into the main combustion space over the said rim,when the piston is at its outer dead center position.

WILHELM GLAMANN.

